dcs5000 repair

[Stubby]

Fly wheel magnets go weak some times .......

[billpierce]

i'll try swapping them then.

 

thanks again for all the advice on this forum!

[billpierce]

Fly wheel magnets go weak some times .......

 

swapped the flywheel and carb now, no difference.

 

i guess the only other thing to try swapping is the coil incase its not working in the cylinder for some reason?

[wisecobandit]

Leave the sparkplug out overnight.

Tomorrow do the usual trick of pouring a good teaspoon of fuel down thru the sparkplug hole, put back in sparkplug and try pulling it over with no choke.

If it fires it will run a bit rough and die but you know you are getting a spark.

 

Assume you have tried a new/known good sparkplug?

 

Ideally it sounds like you could do with a compression check but could be a hole in the intake manifold or similar. Unfortunatly I don't know the saw to be able to comment to much.

Edited September 24, 2015 by wisecobandit

[billpierce]

thanks will try in morning

[billpierce]

well tea spoon if fuel on a dry sparj plug didn;t work. i have tried using the plug, carb and flywheel from my working dcs5000 to no good effect. exhaust was full of fuel/2 stroke so burnt this off, no better.

 

whats the best way to make a comp test kit then - i suspect something is amiss

 

thanks,

 

bill

[wisecobandit]

Most of us prob use a gunson hi gauge compression tester to check engine compression. Available from the likes of Halfords for about £20 which you just screw into the sparkplug hole and pull the engine over 8-10 times. Most engines will run over 100psi but ideally you want 130+

If that's good after that its pressure and vac test which is a bit more complex where you basically block the inlet and outlets of the cylinder and pressurise the crankcase to find if it holds pressure or not. (shows up dodgy crank seals, crankcase mating gasket,cylinder gasket etc if it doesn't.

TRY THESE NEXT THO BEFORE THE ABOVE,

You did pour the fuel into the cylinder plughole onto the piston and then fitted a dry plug and not just poured it on the plug literally didn't you?

After burning off the excess fuel you did try a dry plug and pulled it over a bit more didn't you? (no choke) Sounds like its flooded and with that much fuel around it will drown any spark with excess fuel so wont fire anyway until most of its evaporated/burnt off.

The next thing you could try is disconnecting the wire to the coil and try pulling it over again checking for a spark etc. This would eliminate a dodgy kill switch. Just beware tho if you do this and put the plug in the engine and it starts that you will need to choke it to stall it or block the air filter as the on/off switch will be disable/disconnected.

[billpierce]

Most of us prob use a gunson hi gauge compression tester to check engine compression. Available from the likes of Halfords for about £20 which you just screw into the sparkplug hole and pull the engine over 8-10 times. Most engines will run over 100psi but ideally you want 130+

If that's good after that its pressure and vac test which is a bit more complex where you basically block the inlet and outlets of the cylinder and pressurise the crankcase to find if it holds pressure or not. (shows up dodgy crank seals, crankcase mating gasket,cylinder gasket etc if it doesn't.

TRY THESE NEXT THO BEFORE THE ABOVE,

You did pour the fuel into the cylinder plughole onto the piston and then fitted a dry plug and not just poured it on the plug literally didn't you?

After burning off the excess fuel you did try a dry plug and pulled it over a bit more didn't you? (no choke) Sounds like its flooded and with that much fuel around it will drown any spark with excess fuel so wont fire anyway until most of its evaporated/burnt off.

The next thing you could try is disconnecting the wire to the coil and try pulling it over again checking for a spark etc. This would eliminate a dodgy kill switch. Just beware tho if you do this and put the plug in the engine and it starts that you will need to choke it to stall it or block the air filter as the on/off switch will be disable/disconnected.

 

thanks,

 

yes tried a variety of combinations of different working plugs, blowing the cylinder out with an air line, pulling over with no success. yes after burning the excess fuel out the exhaust, heated a plug up and popped it in, again with no effect..... haven't tried disconnecting the kill switch, but it seems to work grand as with the plug out you can seea good spark, then no spark when kill switch is off....

 

mmmm order one of these gunson hi gauge compression testers, will see if that works.

 

i may be totally wrong but saws with bad comp usually run a bit or at least fire eh? just that they run rough - well this has been my experience anyway.

 

thanks again for all yer help

[shavey]

thanks,

 

yes tried a variety of combinations of different working plugs, blowing the cylinder out with an air line, pulling over with no success. yes after burning the excess fuel out the exhaust, heated a plug up and popped it in, again with no effect..... haven't tried disconnecting the kill switch, but it seems to work grand as with the plug out you can seea good spark, then no spark when kill switch is off....

 

mmmm order one of these gunson hi gauge compression testers, will see if that works.

 

i may be totally wrong but saws with bad comp usually run a bit or at least fire eh? just that they run rough - well this has been my experience anyway.

 

thanks again for all yer help

 

A cheap old method if you can pull the engine over with your finger sealing the plug hole if the compresion is over 70 psi then air will escape past your finger if you've got bad compression then no air will escape

When you pull it over and as you pass through intake you should feel the piston suck your finger I

Thanks

[wisecobandit]

So strong spark and fuel but not firing, think the next step really is a compression test to double check that. No silly mesh screen on the exhaust that could be blocked and the fuel line is good with no leak? You could try the carb/coil on the good saw just to eliminate them having any issue.

 

If that all seems fine then a pressure test is in order as sounds a bit like an air leak somewhere. The saw hasn't been dropped or shows signs of it and got a crack in the crankcase?